Koi Diseases and Their Treatments

by

www.koi-care.com

www.koi-care.com

When it comes to the maintenance of your koi pond, probably the most common task you’ll spend time on is disease prevention and treating diseases that do arise.

www.koi-care.com

The more you know about koi maladies, the better you can treat them.

BELOW ARE SOME OF THE MORE COMMON KOI DISEASES AND THEIR TREATMENTS.

www.koi-care.com

1. ICHOne of the most common diseases found in Koi is Ich(aka; White Spot disease). It is a protozoan that begins its growth in the pond and later attaches to the gills of the Koi as it matures.

TREATMENT:For short treatments in quarantine, one could do a quantity of 1.5 mg of malachite green for every liter of water for up to 1 hour (or 6mg of malachite green for every gallon of water). Always wear gloves when handling both malachite green and formalin.

www.koi-care.com

2. DROPSY (PINECONE DISEASE)Fish that have dropsy often show signs of swelling or lifting of the scales. Their eyes will frequently bulge. If you ever notice this, don’t hesitate to separate the infected fish from the others.

TREATMENT:Dropsy is, more or less, terminal. By the time you see your fish bloated with standing scales it means that there is kidney and liver failure. Prevention of infection to your other fish is recommended with Medi Koi or Debride RX.

www.koi-care.com

3. TAIL ROTTail rot and fin rot are really secondary to the original problem which could be stress or poor water quality that is causing your koi to be immuno-compromised in the first place.

TREATMENT:One good start to treating this malady is by a 30 -50% water change of your pond. Using Mela-Fix is also a great option for dealing with the bacteria themselves and you can also add salt to your pond which will go to work on your bacteria and also lower stress levels for your koi.

www.koi-care.com

4. MOUTH ROTMouth rot is a symptom of something larger and that is usually poor water quality that is causing your fish’s health to be compromised and open to infection.

TREATMENT:You’re going to want to stop feeding for the time being and start improving your water quality by doing a 30% water change. Next thing would be a light salt bath treatment and perhaps a treatment of Mela-Fix.

www.koi-care.com

5. CHILODONELLASome of the symptoms included with this protozoan parasite are: dying on the surface and rolling over on the fish’s s sides. This is a notorious killer of koi.

TREATMENT:You will want to increase the salt concentration in the pond for 2 weeks as well as increasing aeration.

www.koi-care.com

6. AEROMONAS BACTERIAThese bacteria are associated with ulcers and fin erosion.

TREATMENT:The koi will need to injections of Chloramphenicol. This treatment should yield positive results in 3-4 days.

www.koi-care.com

7.PSEUDOMONAS BACTERIALike its cousin, aeromonas, this bacteria is also associated with ulcers and fin erosion.

TREATMENT:Infections of this nature will require an injection of Baytril.

www.koi-care.com

8. COLUMNARISThis bacteria will attack sites of injury but will cause fin, tail and mouth rot. Additionally fish can be vulnerable to it during times of stress. Your fish may develop a white film on their skin and display sunken in eyes. It can be a rapid killer so be sure to take swift action.

TREATMENT:Feeding your koi Medi-Koi or Debride RX will definitely help your fish with an “inside out” treatment strategy.

www.koi-care.com

9. ANCHOR WORM (LERNEA)Anchor worm, also known as Lernea is a crustacean parasite that attaches to, and digs into the skin of fish. The female Lernea attaches to fish while males do not. The worm feeds on the fish, damaging its tissue.

TREATMENT:They can be removed using tweezers or other small pincers. After removal, rub some Neosporin on the infected area. Use Dimilin, Dylox or Lufenuron to treat the pond.

www.koi-care.com

10. ARGULUS (FISH LICE)These unwanted invaders have eight legs and rounded bodies. They also have to big suckers which are used to attach to the fish. Their appearance leads to their nickname, “fish lice”. These parasites can cause considerable irritation to fish and can lead to bacterial infections.

TREATMENT:As with anchor worm, treatment will consist of Dimilin but another product also works as well, Lufenuron. You should see positive results in a matter of days.

www.koi-care.com

11. FUNGUSSome causes of fish infections, such as fungal hyphae or spores, require a microscope to see them. Mild or moderate infections can be treated and possibly cured if they are caught early. These types of fungal infections are not typically contagious and usually only a single Koi becomes infected.

TREATMENT:Fungus can be removed by gently rubbing the area with a cotton swab while the infected area must be treated with an antibiotic or antimicrobial cream immediately afterwards.

www.koi-care.com

12. LYMPHOCYSTISYour Koi fish may have Lymphocystis if its displaying any buff discoloration on its skin. Another sign of Lymphocystis is rough, raised lesions on its skin.

TREATMENT:You will want to put the infected fish in a quarantine tank and increase the heat. There is a treatment containing “neutral acriflavine” that will help defeat the virus (this product takes the brand name “Lymphocystis Cure”). It is entirely possible and not uncommon for the virus to go away on its own.

www.koi-care.com

13. EPISTYLIS Epistylis is an uncommon parasitic infection that is dangerous and can cause other diseases in your Koi. It is usually caused by poor management of the water, resulting in dirty water infected with parasites.

TREATMENT:Change the water in the pond and add salt (0.3% concentration) to combat these parasites. One can also put the affected fish in quarantine for 2 weeks while raising salt levels to 0.3%.

www.koi-care.com

14. SKINNY DISEASEThe disease is caused by a bacterial infection that causes the fish to have a sucked-in gill appearance. Its head will often appear much bigger than the rest of its body.

TREATMENT:Adding extra food to the fish’s diet can usually clear up this disease. However, sometimes this doesn’t help and if the bacterial infection persists, adding erythromycin to the fish’s food normally clears the infection up quickly.

www.koi-care.com

15. CARP POXYour Koi fish may have Lymphocystis if its displaying any buff discoloration on its skin. Another sign of Lymphocystis is rough, raised lesions on its skin.

TREATMENT:There is no effective treatment for this virus but fortunately it usually goes away on its own. Gradually heating the water may expedite the virus diminishing. For some pond owners this is just something that shows up every winter and spring and goes away with the onset of summer.

www.koi-care.com

16. SPRING VIREMIA OF CARP (SVC)As the name suggests, this viral disease likes cold water and shows up in spring when the water is still cold and your koi’s immune system is not in full swing. Some of the symptoms that you may see are a reddening of the skin and swim bladder inflammation.

www.koi-care.com

17. HEXAMITAThis disease also known as “hole in the head” disease is protozoan parasite responsible for lesions in the dermal layers of koi. You will notice your koi being lethargic and, more definitively, you will notice an erosion of the skin (and usually the fins as well).

TREATMENT:As with many diseases, you will want to quarantine this fish. You will also want to establish a treatment course with a product called Flagyl for 10-12 days.

www.koi-care.com

18. COTTON WOOL DISEASEAnother disease Koi sometimes suffer is called Columnaris, which is sometimes also called Cotton Wool Disease. White threads in the fish’s mouth and a dry skin appearance are the main characteristics of this disease.

TREATMENT:You can put potassium permanganate in the water to help clear up the condition. Additionally, injecting antibiotics and treating the wound directly will help care for the disease.

www.koi-care.com

19. FLUKESThere are two main classes of flukes; 1) gill flukes and 2) skin flukes. Both kinds are microscopic so if you suspect your fish are suffering from flukes you will need a microscope to verify it. Dactylogyrus or gill flukes will attach to the gills and, as the name suggests, body flukes or gyrodactylus attach to the body.

TREATMENT:You can quarantine but it is likely that your entire pond is afflicted with the flukes or their eggs so you can treat with medications like Aqua Prazzi, potassium permanganate or Fluke Solve (both AquaPrazzi and Fluke Solve have the same active ingredient; “praziquantel”).

www.koi-care.com

20. OODINIUM PARASITESThe disease caused by these parasites is sometimes called Velvet Disease because it resembles a velvety golden dust, which covers the fish. Other symptoms include ragged fins and a loss of scales and skin. Though it is somewhat rare there are treatments.

TREATMENT:Adding salt to the pond’s water does not normally clear up Velvet Disease. The best option is to add 37% Formalin to the water as this has been shown to be most effective. Alternatively, Simazine can also be used to treat oodinium.

www.koi-care.com

21. COSTIACostia, like Flukes, are a parasite. In this case it is a microscopic flagellate that can reproduce rapidly. Typically koi don’t suffer from costia unless they are already compromised in some way to begin with so it would be classified as a secondary illness.

TREATMENT:There are treatment options for costia. Malachite green and 37% formalin can be used but you will need to make sure there is no salt in the pond to start with. If this treatment is chosen be sure to increase aeration.

www.koi-care.com

22. POP EYEPop eye is also called exophthalmia and is really not linked to any one illness but is more of a symptom of something more. It is a direct response to an excess of fluid or possibly gasses built up behind the eye which then cause the eye to bulge is distend.

TREATMENT:The best course of action is to immediately quarantine the fish and do a light salt bath. You will also want to greatly reduce feeding and how much you give it. You will also want to do 25% water changes daily and monitor water quality on a regular basis.

www.koi-care.com

23. CLOUDY EYECloudy eye is somewhat uncommon but it can occur. This malady is typically a symptom of something else going on rather than something attacking the eye specifically.

TREATMENT:Treatments for cloudy eye are a medicated koi food formulated to handle fungal and bacterial issues called Medi-Koi and or Mela-Fix. Mela-Fix is actually an oil extract from the Melaleucatree mostly occurring in Australia and it has natural anti-bacterial properties.

www.koi-care.com

24. LEECHESUnfortunately, leeches aren’t just looking for a free ride but also a free meal and eventually they will cause mortality of the host fish if left untreated. Leeches can also transmit the koi disease known as SVC.

TREATMENT:Some treatments for leeches include a product called Masotenwhich comes in powder form. Another product is called malathion however many recommend against this treatment as it is an organophosphate insecticide and though it will kill leeches it may also harm your koi in the process.

www.koi-care.com

25. ULCERSUlcers on the skin of your fish result from bacterial infections that form on scales, causing them to become red. The infection causes holes, or ulcers on the exterior of the fish and will eventually result in loss of scales if left untreated.

TREATMENT:Maintain a healthy, clean pond and treat ulcers with a topical antibacterial such as Panalog to stop the bacteria in their tracks.

www.koi-care.com

26. SAPROLEGNIA FUNGUSOne of the most common fungal infections found in Koi fish comes from the Saprolegnia fungus. Spores from the fungus can grow on any part of the fish, including its gills. The fungus first attacks the fish by germinating on dead tissue.

TREATMENT:The afflicted fish will need to be isolated in a quarantine tank with the temperature raised to at least 77 degrees F. Additionally, it will be very beneficial to also get your salt levels up to around 0.3%.

www.koi-care.com

27. TRICHODINAOne of the easiest protozoan parasites to see under a microscope, and subsequently confirm your fish is infected, is Trichodina. An infection of this parasite can be detected by a gray-white opaque appearance on the body of infected Koi.

TREATMENT:Treat this disease with a five day course of increased salinity (0.5 to 0.6%). Due to increasing tolerance of some organisms to salt treatments a course of formalin may be necessary.

www.koi-care.com

28. KOI HERPES VIRUS (KHV)This virus is a potent one. Some of the effects of this disease are sloughing off of the skin which leaves the koi vulnerable to bacterial infection. Your koi will be lethargic and have sores and lesions on its skin, gills and fins.

TREATMENT:Increase salt concentration to around 0.45% and bring the water temperature up about 1 degree F every hour until it gets to 87 degrees. The fish should remain in this situation for 4 days during which medicated food such as Medi Koi should be fed.

www.koi-care.com

29. GILL MAGGOTAnother parasite sometimes infecting Koi is the gill maggot. The parasite most often attacks the Koi’s gills and has a maggot-like egg sac appearance. It is a relatively uncommon parasite sometimes found in Koi ponds but when present, can cause Koi quite a bit of irritation.

TREATMENT:The product Lice-Solve has been shown to be effective against gill maggots (as well as argulus) but you will need to increase aeration. You can treat the whole pond or individual fish in quarantine.

Click here to learn more about koi diseases and their treatments.

Clearly there are quite a few little “beasties” out there that can make life

miserable for your koi. The good news is that there are a lot more options for

treatment these days than there was say 100 years ago.

www.koi-care.com